E. coli, Shigella and Salmonella Infections: How They Spread
The strains of E. coli, Shigella and Salmonella that cause illness in humans are what are called enteropathogenic bacteria. Pathogenic meaning they cause harmful infectious diseases and enteric refers to the fact that the infections they cause are in the intestine.
The enteric infections caused by these pathogens are dependent on whether the bacteria are able to colonize in the intestine. Research from a Brazilian university is helping to better understand the variety of “strategies” these pathogens use to multiply inside their hosts and infect them. According to the research:
“Diarrhea-causing pathogens employ a variety of sophisticated strategies to colonize the intestinal epithelium [tissue lining the intestine].” In essence, ingested pathogens have evolved the abilities to:
- Resist many of the host’s defenses such as stomach acidity, peristalsis, mucosal cell exfoliation, intestinal mucins, and bacteriocins
- Adhere to intestinal epithelia (tissue).
- Ultimately colonize that tissue.
Sometimes that colonization involves cellular invasion. When that happens, the bacteria can spread to other tissues in the host’s body. According to the research, the pathogens attack cells in the host’s body. “The host cell, in turn, defends itself against infection by initiating an inflammatory response and by altering the intestinal fluid balance in order to extrude the unwanted bacteria, thus causing diarrhea.” Therefore, whether the infection is “successful” depends upon complex interactions between the bacteria and the host cells. The bacteria’s mission, basically, is to exploit cell machinery for their own benefit.
Source:
http://www.gutpathogens.com/content/2/1/8
Tags: e coli infection, ecoli poisoning
